For the first time, the growth details and photoluminescence properties of ultra-thin InN insertions embedded in GaN nanowires are presented. The InN insertions embedded in GaN nanowires exhibit photoluminescence in the range of 2.9–3.35 eV, where the most intense emission line at 3.17–3.23 eV is tentatively attributed to monolayer-thick InN insert based on comparative spectral analysis. These findings can be promising for the development of single-photon sources and Wigner quantum dots operating from cryogenic to elevated temperatures.